dngu: synthesis, formulation and testing of an affordable, less-sensitive energetic ... · ·...

Non Export Controlled. Releasable to Foreign Persons. S2DSEA2012-0167

DNGU: Synthesis, Formulation and Testing of an

Affordable, Less-Sensitive Energetic Material

Dr. David Price, Dr. Jacob Morris, Brian Alexander, Matt Hathaway

Presented by Dr. Neil Tucker

BAE Systems Ordnance Systems

May 2012

Non Export Controlled. Releasable to Foreign Persons. S2DSEA2012-0167 Non Export Controlled. Releasable to Foreign Persons. S2DSEA2012-0167

• DNGU has been known for years and has been studied by Chinese and

French researchers.

• It was evaluated in the 1980s as a potential high performance explosive to

replace HMX.

However, its measured performance did not match the predicted performance

and was subsequently abandoned.

• Its actual properties may better lend itself to be used as an IM ingredient,

being slightly less powerful than RDX and NTO, and as a potential

replacement for NQ or TATB in some formulations.

• It also has the advantage of being a very affordable explosive ingredient,

with a projected cost between RDX and HMX

DNGU-Background

2

Non Export Controlled. Releasable to Foreign Persons. S2DSEA2012-0167 Non Export Controlled. Releasable to Foreign Persons. S2DSEA2012-0167 3

DNGU-Properties

• DNGU may be comparable to

TATB in terms of sensitivity

and superior in performance.

• Although VoD may be

somewhat low, high density of

DNGU boosts performance

• Data from multiple sources is

contradictory at times

It was decided that DNGU

needed to be evaluated in-

house in an effort to resolve

discrepancies and determine

the potential applications of

DNGU

• DNGU has been shown to

have a faster burn rate (1.2x)

than HMX.

RDX NQ DNGU TATB NTO

m.w. (g) 222.1 104.1 232.1 258.2 130.1

Oxygen Balance (%) -21.6 -30.7 -27.6 -55.8 -21.6

Nitrogen Content(%) 37.84 53.83 36.21 32.55 43.07

Vol. Explosive gases(

l/kg) 903 1042 * * 855

Heat of Explosion

(kJ/kg) 6322 2730 * 3062 2993

Density (g/cc) 1.82 1.71 1.94, 1.97 1.938 1.91

lead block test (cc/10g) 480 305 * 175 *

VOD (m/s) 8750 8200

7580,8450,

8950

7350,

7950 7860

Impact Sensitivity (Nm) 7.5 49

5

(questionable) 50 1200

Friction Sensitivity (N) 120 353 200-300 353 353

Impact Sensitivity (cm) 30 >177, 73 88-124 >177 292

Impact Sensitivity (J)-

Julius Peters 5.5 * 8

30 kg shock drop height

on 100g (meters) 2.5 * >4 >4

Card gap test (cards) * * 210 190

SSGT

NA (11.8%

voids)

0.18 mm (11%

voids)

0.51 mm

(12%

voids)

Pressure CJ (GPa) 34.6 27.4 34.2 31 ~28

DSC (onset of exotherm) 220 210

210-234, 240-

250 350 270


DNGU-Synthesis

• DNGU is produced from a simple nitration of glycoluril (inexpensive)

Glycoluril produced from very inexpensive materials (urea and glyoxal)

Glycoluril is commercially available and can be made at HSAAP

• Cost of DNGU estimated to be between RDX and HMX

• OSI R&D has made over 40 pounds of DNGU.

• Currently optimizing synthesis process

Original DNGU product particle size was ~15-20 microns

New route can provide much larger material (200-300 microns)

Yields typically 90-95% with purities >99%

4


DNGU-Reaction Calorimetry

5

Batch Enthalpy per Mole Glycoluril ΔT(ad)

1106-17 -97.6 kJ/mol 65.0 oC

1106-19 -101.8 kJ/mol 75.8 oC

• Reaction calorimetry (RC1) performed to quantify

exotherms and assess scale-up safety

• Batch 1106-17: 0.5 lb batch

• Batch 1106-19: 1.0 lb batch

• Exothermicity of reaction appears relatively mild

(especially for a nitration)

• Reaction deemed safe for scale-up within R&D

•Mild, straight-forward, easily-controlled synthesis


DNGU-Thermal Analysis

6

• DNGU has no melting

point before

decomposition.

• DNGU has sharp

exothermic transition at

245-250°C

• Between RDX (200-

250°C) and NTO (270-

280°C)

• DNGU seems to have

a faster decomposition

rate than RDX.

• VTS: 0.41 cc/g

• Future planned work

includes TGA and ARC

(accelerated rate

calorimetry)


DNGU-Analytical

7

• Impact Sensitivity: 80-100 cm (Holston apparatus)

• RDX: 17 cm

• Friction Sensitivity: >360 N

• RDX: 164 N

• Surface Area (BET): 1.3-1.4 g/m2

• Particle Size (typical below):


DNGU-SEM Analysis

• DNGU material from early in development

program has rough “coral reef” appearance

and looks like agglomerates of small

particles.

Probably not good for formulating

• However, there appear to be large crystals

hiding in some of the “agglomerates”…..

8


DNGU SEM Analysis

• DNGU produced after optimization efforts has more defined and larger

crystal shapes

9


DNGU Formulations

10

• DNGU was coated with 5% Viton

through a standard Holston

slurry coating process.

• 2.5 lb batch size

• RDX was processed same as

DNGU.

• Purpose: Prepare coated DNGU

and RDX for pellet pressing and

performance/sensitivity evaluations.

• No optimization performed at this

time.

• DNGU is compatible with:

RDX,HMX,C-4 binder, TNT, Aluminum,

DNAN, Viton

RDX molding powder

Impact: 70 cm Impact: 200 cm

DNGU molding powder


DNGU Molding Powder

• Over 150 pellets of each formulation were pressed

• Average press densities

DNGU: 1.65-1.66 (84% TMD)

RDX: 1.65-1.66 (91%TMD)

11

DNGU pellet RDX pellet


DNGU-Cheetah Calculations

• DNGU coated with 5% Viton compared against RDX (class 1) coated with

5% Viton and TATB (PBX-9502).

12

•At high TMD, DNGU comparable to RDX. At low TMD, DNGU

comparable to TATB

%TMD Density VoD

(m/s)

Pressure

(GPa)

DNGU 98 1.93 8400 31.0

RDX 98 1.78 8444 31.8

TATB 98 1.89 8015 27.0

DNGU 84 1.65 7200 21.7

RDX 91 1.65 8000 27.2

TATB 86 1.65 7300 20.8


DNGU Testing-Performance

• VoD and Blast pressure measured together

(unconfined)

• Pressure measured at 5, 10, and 15 feet

intervals.

• DNGU pressure: ~73% of RDX

(TATB: PBX—9502 (95% TATB) has a

pressure of ~ 76% of RDX/Viton-calculated at

similar TMD)

• RDX /Viton VoD: ~8000 m/s

• DNGU/Viton VoD: ~7600 m/s

(TATB: PBX—9502 (5% KelF) has a VoD of

~7600 m/s)

Reported value

• All data is preliminary.

13

•Data indicates DNGU has TATB-like performance


DNGU Testing-LSGT

• DNGU coated with 5% Viton

compared against RDX

(class 1) coated with 5%

Viton

• DNGU: 130 cards

• RDX: 301 cards

• (TATB: PBX—9502 (5%

KelF) has a card gap of

approximately 70 cards (50%

point at 97% TMD))

14

•DNGU is much less shock-sensitive than RDX


Conclusions

• DNGU is an affordable, insensitive energetic material that may find use

in explosives and propellants

• DNGU shows promise as:

• An alternative to TATB (better on cost)

• An alternative to NTO (no water solubility)

• A way to reduce use of RDX in energetic formulations


Path Forward

• Further development (synthesis and recrystallization) needed to optimize

particle shape and size.

• Evaluate DNGU as a TATB alternative in pressable formulations such as

PBXN-7 and PBXW-14.

• Evaluate DNGU as an NTO alternative in melt-pour formulations such as

IMX-101 and IMX-104.

• Use these formulations to generate more performance (VoD, pressure)

and sensitivity (LSGT) data for DNGU

• Evaluate DNGU for propellant applications.


Acknowledgements

• Kelly Guntrum

• Robyn Wilmoth

• Jim Haynes

• Alberto Carrillo

• Dr. Jeremy Headrick

POC: David Price,

423-578-6350,

[email protected]

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